W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > October to December 2006

Re: Go ahead with pub

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 02 Oct 2006 11:06:06 +0100
Message-ID: <4520E48E.2020004@hp.com>
To: Bijan Parsia <bparsia@cs.man.ac.uk>
CC: RDF Data Access Working Group <public-rdf-dawg@w3.org>



Bijan Parsia wrote:
> Sorry to be late, but there was some confusion about what was going  
> on and then I hit the class part of the week.
> 
> I think the status part should point to the issues list.
> 
> """Costs: Tableau-based reasoners (at least, the Pellet Demo example  
> 7) rely on the current, more expressive semantics to match  
> implications that are not in a materializable RDF graph."""
> 
> No. Pellet uses BNodes as syntax for non-distinguished variables, as  
> that's what we were told was the likely syntax for non-distinguished  
> variables in SPARQL/DL. The semantics of *all* variables in SPARQL/ 
> RDF is semi-distinguished.

I'd be interested in tracing this back sometime.  Who told you/Pellet and does 
  the working group have a record of it?  I'd find it useful in bring some of 
the themes together as there is a lot of material scattered over the email 
archive.

> I thought the alternative proposal (e.g., from conversation with  
> Jeen, Jorge and others) was to *drop* BNodes in triple patterns. That  
> does solve all the problems of scope, meaning etc., but it means that  
> certain combinations of the axes of distinguishedness will be harder  
> to specify (but heck, we can always introduce syntax later).
> 
> """@@ Now we are in CR, shouldn't this be deleted?  Need chair's  
> permission.
> The working group decided on this design and closed the disjunction  
> issue without reaching consensus. The objection was that adding UNION  
> would complicate implementation and discourage adoption. If you have  
> input to this aspect of the SPARQL that the working group has not yet  
> considered, please send a comment to public-rdf-dawg-comments@w3.org."""

> 
> I would like that to be deleted because it's confusing on several  
> levels (e.g., why doesn't it apply in optional?) I don't particularly  
> care that it'd done before pub, but it seems an easy enough move. I  
> mean, it doesn't *change* anything!

This text does seem out of date: the objection from DaveB was withdrawn and I 
can't find a record of any other (I just checked with Steve).

http://www.w3.org/2001/sw/DataAccess/issues#disjunction

It is confusing.  But I'd like the chair's permission as confirmation.

	Andy
> 
> """Current conventions for DESCRIBE return an RDF graph without any  
> specified constraints. Future SPARQL specifications may further  
> constrain the results of DESCRIBE, rendering some currently valid  
> DESCRIBE responses invalid. As with any query, a service may refuse  
> to serve a DESCRIBE query.""""
> 
> I have other comments, both editorial and substantial, but they are  
> for post publication, I think.
> 
> Cheers,
> Bijan.
> 
Received on Monday, 2 October 2006 10:06:44 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:27 GMT